Lead delivery device and method

ABSTRACT

A lead delivery apparatus and a method of delivering a medical lead to an anatomic target site. The method includes inserting a hydraulic plug into an internal delivery lumen of a delivery shaft, and coupling a medical lead to the hydraulic plug. Hydraulic pressure is applied to the hydraulic plug through the delivery lumen, thereby moving the hydraulic plug toward an anatomic target site, and advancing the medical lead toward the target site.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/183,401, filed Jul. 31, 2008, which claims the benefit ofU.S. Provisional Application No. 61/076,183, filed on Jun. 27, 2008.

This application continuation-in-part of U.S. patent application Ser.No. 12/495,844, filed Jul. 1, 2009, which claims the benefit of U.S.Provisional Application No. 61/182,205, filed May 29, 2009.

This application is related to U.S. Ser. No. 12/183,105, filed Jul. 31,2008, which claims the benefit of U.S. Provisional Application No.61/076,183, filed on Jun. 27, 2008.

This application is related to U.S. patent application Ser. No.11/468,910 filed on Aug. 31, 2006, which is a division of U.S. patentapplication Ser. No. 10/254,196, filed on Sep. 24, 2002, now U.S. Pat.No. 7,107,105.

The disclosures of the above applications are incorporated herein byreference.

INTRODUCTION

Various cardiac devices providing electrical stimulation, rhythmmanagement, or resynchronization therapy to the heart includeimplantable electrically conductive leads in contact with excitableheart or other body tissue.

The present teachings provide a device and method for delivering animplantable electrically conductive lead to a target site for a use witha cardiac device.

SUMMARY

The present teachings provide a medical apparatus that includes animplantable electrically conductive lead for a cardiac device, the leadhaving an internal bore terminating at a distal lead opening, and a leaddelivery device for delivering the distal end of the lead to a bloodvessel during implantation of the lead. The lead delivery deviceincludes a removably anchorable guidewire, and a fixator attached to adistal portion of the guidewire for anchoring the guidewire. The fixatoris movable between a compact configuration and an expandedconfiguration. The fixator is capable of passing through the distal leadopening of the lead in the compact configuration. The fixator is capableof exerting a holding force in the range of about 0.89 to 4.45 N in thelumen of the blood vessel in the expanded configuration.

The present teachings also provide a medical method that includesinserting a distal end of cannulated catheter through cardiac tissueinto a main cardiac vessel, attaching an expandable fixator to a distalportion of a guidewire, inserting the guidewire through the catheter,advancing the guidewire past the distal end of the catheter and into atarget site in a lumen of a branching vessel, expanding the fixator intothe target site, removably anchoring the fixator into the lumen with aholding force in the range of about 0.89 to 4.45 N, and removing thecatheter. The method further includes advancing an implantableelectrically conductive lead of a cardiac device over the guidewire tothe target site without moving the guidewire while tensioning theguidewire, and delivering the distal portion of the lead at the targetsite.

In another aspect, the present teachings provide a medical apparatusthat includes a cardiac device for providing cardiac therapy, or cardiacsensing, or a combination thereof, an implantable electricallyconductive lead having proximal and distal ends, the proximal endcouplable to the cardiac device, the lead having an internal boreterminating at a distal opening at the distal end, and a lead deliverydevice for delivering the distal end of the lead to a blood vesselduring implantation of the lead. The lead delivery device includes aremovably anchorable guidewire, and a fixator attached to a distalportion of the guidewire, the fixator movable between a compactconfiguration and an expanded configuration. The fixator has a compactwidth less or equal to about 0.483 mm and is capable of passing throughthe distal lead opening of the lead in the compact configuration. Thefixator has an expanded width up to about 5 mm, and is capable ofexerting a holding force in the range of about 0.89 to 4.45 N in thelumen of the blood vessel in the expanded configuration.

In a further aspect, the present teachings provide a medical apparatuscomprising a guidewire and a fixator catheter. The fixator cathetercomprises a tubular body with a distal portion and a proximal portion.The fixator catheter further comprises a distal opening, a fixatorsecured to the distal portion, and a body opening arranged between thefixator and the proximal portion. The guidewire is passed through thebody opening and the distal opening of the fixator catheter. The fixatoris movable between a compact configuration and an expandedconfiguration.

In yet another aspect, the present teachings provide a medical methodcomprising passing a guidewire through a fixator catheter. The fixatorcatheter comprises a tubular body with a distal portion and a proximalportion. The fixator catheter further comprises a distal opening, afixator secured to the distal portion, and a body opening arrangedbetween the fixator and the proximal portion. The guidewire is passedthrough the body opening and the distal opening of the fixator catheter.The method further comprises navigating the guidewire and fixatorcatheter to a desired site. At the desired site, the fixator is expandedto an expanded configuration in order to releasably secure the fixatorcatheter. An implantable electrically conductive lead of a cardiacdevice is advanced over the guidewire to the desired site while thefixator is deployed.

In various embodiments, the present teachings provide a lead deliveryapparatus comprising an electrically conductive lead for an implantablemedical device, a delivery shaft for delivering the lead to a targetsite, a fixator and a pulley structure. A flexible member is coupled tothe delivery shaft and the lead and engages the pulley structure suchthat pulling a first portion of the flexible member moves the lead tothe target site.

In various embodiments, the present teachings provide a method ofdelivering a medical lead to an anatomic target site. The methodincludes providing a delivery shaft and a fixator attached to a distalportion of the delivery shaft. The method also includes passing aflexible member having first and second ends through a longitudinalpassage of the delivery shaft in a first orientation, around a pulleystructure and out of the delivery shaft in a second directionsubstantially opposite to the first orientation such that a first end ofthe flexible member remains outside the deliver shaft. The method alsoincludes inserting the lead delivery shaft loaded with the flexiblemember on a distal portion of the delivery shaft through cardiac tissue,fixating the fixator to a target site in a blood vessel, and coupling alead over a portion of the flexible member associated with the seconddirection. Pulling the first end of the flexible member away from theproximal end of the delivery shaft in a first direction, advances thelead toward the target site in a second direction substantially oppositeto the first direction.

In various embodiments, the method includes inserting a guidewire tocardiac target site, and providing a catheter with a fixator and aflexible member having first and second ends and coupled to a pulleystructure. The method includes positioning the catheter over theguidewire and fixating the catheter at the target site with the fixator.The method also includes coupling a medical lead to the flexible member,pulling the first end of flexible member in a first direction away fromthe target site, and advancing the lead to the target site. Theguidewire and the catheter are removed.

In various embodiments, the present teachings provide a method ofdelivering a medical lead to an anatomic target site. An elongated leadadvancement member is coupled to a delivery shaft. The delivery shaft isinserted to the target site. The delivery shaft is temporarily attachedto the target site using a fixator. A medical lead is inserted over thelead advancement member and pushed over the lead advancement membertoward the target site.

In various embodiments, the method includes inserting a delivery shaftto the target site, coupling a medical lead to an elongated leadadvancement member, slidably coupling the lead advancement member to thedelivery shaft, and attaching the delivery shaft to the target siteusing a fixator. The elongated lead advancement member is pushed alongthe delivery shaft toward the target site, and the medical lead isadvanced toward the target site.

In various embodiments, the method includes inserting a lead advancementmember into a delivery lumen of a delivery shaft, threadably couplingthe lead advancement member to a nut which is slidably and non-rotatablyreceived in the delivery lumen, and coupling a medical lead to the nut.Rotating the lead advancement member advances the nut and the medicallead toward the target site.

In various embodiments, the method includes inserting a hydraulic pluginto an internal delivery lumen of a delivery shaft and coupling amedical lead to the hydraulic plug. Applying hydraulic pressure to thehydraulic plug through the delivery lumen moves the hydraulic plug andthe medical lead toward the target site.

In various embodiments, the method includes inserting a hydraulic pluginto a first internal delivery lumen of a delivery shaft and coupling amedical lead to the hydraulic plug. Hydraulic pressure is applied to thehydraulic plug through a second delivery lumen which is separate fromand substantially parallel to the first delivery lumen and communicateswith the first delivery lumen through a U-shaped junction. The pressuremoving the hydraulic plug, and advancing the medical lead toward thetarget site.

In various embodiments, the method includes inserting a hydraulic pluginto an internal delivery lumen of a delivery shaft and coupling amedical lead to the hydraulic plug. Applying vacuum suction to thehydraulic plug through the delivery lumen moves the hydraulic plug andadvances the medical lead toward the target site.

In various embodiments, the method includes inserting a medical leadinto an internal delivery lumen of a delivery shaft, applying hydraulicpressure to an enlarged distal portion of the medical lead, andadvancing the medical lead toward the target site.

The present teachings provide a lead delivery device. In variousembodiments the lead delivery device includes a medical lead, anelongated delivery shaft insertable to an anatomic target site of apatient, and an elongated lead advancement member coupled to a ring. Thering slidably surrounds the delivery shaft. A flexible member outsidethe delivery shaft couples the medical lead to the ring such thatpushing the lead advancement member toward the target site advances themedical lead toward the target site.

In various embodiments the lead delivery device includes a medical lead,an elongated delivery shaft insertable to an anatomic target site of apatient, and an elongated lead advancement member slidably received intoa delivery lumen of the delivery shaft. A flexible member couples themedical lead to the delivery shaft such that pushing the leadadvancement member toward the target site advances the medical leadtoward the target site.

In various embodiments the lead delivery device includes a medical leadand an elongated delivery shaft insertable to an anatomic target site ofa patient. The delivery shaft has a longitudinal delivery lumencommunicating with a longitudinal open slot of the delivery shaft. Aninternally threaded nut is slidably received in the delivery lumen andincludes an external tab slidably received in the longitudinal slot. Anelongated lead advancement member threadably engages the nut through thedelivery lumen of the delivery shaft. A flexible member coupling themedical lead to tab such that rotating the lead advancement memberadvances the nut and the medical lead toward the target site.

In various embodiments the lead delivery device includes a medical leadand an elongated delivery shaft insertable to an anatomic target site ofa patient. The delivery shaft has a longitudinal delivery lumencommunicating with a longitudinal open slot of the delivery shaft. Ahydraulic plug is slidably received in the delivery lumen. A flexiblemember couples the medical lead to the hydraulic plug through the openslot, such that pressure exerted to the hydraulic plug through thedelivery lumen advances the hydraulic plug and the medical lead towardthe target site.

In various embodiments the lead delivery device includes a medical leadand an elongated delivery shaft insertable to an anatomic target site ofa patient. The delivery shaft has a longitudinal delivery lumen with aclosed channel cross-section. A hydraulic plug is slidably received inthe delivery lumen. A flexible member couples the medical lead to thehydraulic plug such that pressure exerted to the hydraulic plug throughthe lumen advances the hydraulic plug and the medical lead toward thetarget site.

In various embodiments the lead delivery device includes a medical leadand an elongated delivery shaft insertable to an anatomic target site ofa patient. The delivery shaft has a first longitudinal delivery lumenand a second longitudinal delivery lumen separate from and substantiallyparallel to the first delivery lumen and communicating with the firstdelivery lumen through a U-shaped junction. A hydraulic plug is slidablyreceived in the first delivery lumen. A flexible member connecting themedical lead to the hydraulic plug and passing by a pulley structuretherebetween, such that applying pressure through the second deliverylumen in a direction toward the target site moves the hydraulic plug inthe opposite direction and advances the medical lead toward the targetsite.

In various embodiments the lead delivery device includes a medical leadand an elongated delivery shaft insertable to an anatomic target site ofa patient. The delivery shaft has a longitudinal delivery lumen with aclosed channel cross-section. A hydraulic plug is slidably received inthe delivery lumen. A flexible member connects the medical lead to thehydraulic plug and passes by a pulley structure therebetween, such thatapplying vacuum suction through the delivery lumen in a direction awayfrom the target site moves the hydraulic plug away from the target siteand advances the medical lead toward the target site.

In various embodiments the lead delivery device includes an elongateddelivery shaft insertable to an anatomic target site of a patient. Thedelivery shaft has a longitudinal delivery lumen and a side openingcommunicating with the delivery lumen. A medical lead has an enlargeddistal portion and is inserted into the delivery lumen such that theenlarged distal portion is distal to the side opening. A flexiblesealing member at the proximal end of the delivery shaft surrounds themedical lead such that applying pressure through the side openingadvances the medical lead toward the target site.

In various embodiments, the lead delivery device includes a deliveryshaft having a longitudinal lumen and a temporary fixator, a leadadvancement member having a distal end, a connector coupling the distalend of the lead advancement member to the delivery shaft, and a medicallead coupled to the lead advancement member.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 1A is an environmental view of the lead delivery device of FIG. 1,shown in a second aspect;

FIG. 1B is an enlarged detail of the lead delivery device of FIG. 1B;

FIG. 2 is a perspective environmental view of the cardiac device withthe lead implanted after the lead delivery device of FIG. 1B is removed;

FIG. 3 is a plan view of a lead delivery device having a fixatoraccording to the present teachings, the lead delivery device shown withthe fixator in an expanded configuration;

FIG. 4 is a plan view of a lead delivery device having a fixatoraccording to the present teachings, the lead delivery device shown withthe fixator in a compact configuration;

FIGS. 5-11 illustrate various fixators for a lead delivery deviceaccording to the present teachings;

FIG. 11A is a top view of the fixator of FIG. 11;

FIG. 12 is a side view of the fixator of FIG. 11, illustrating adeployment mechanism;

FIG. 13 is a sectional view of a lead delivery device according to thepresent teachings with a fixator in a compact configuration inside alead;

FIG. 14 is the lead delivery device of FIG. 13, shown with the fixatorin an expanded configuration outside the lead;

FIG. 15 is the lead delivery device of FIG. 13, shown with the fixatorpartially retracted inside the lead;

FIG. 16 is an end view of a distal end of an electrical lead with anoffset distal opening;

FIG. 17 is a plan view of a lead delivery device having a fixatoraccording to the present teachings, the lead delivery device shown withthe fixator in a compact configuration;

FIG. 18 is a plan view of a lead delivery device having a fixatoraccording to the present teachings, the lead delivery device shown withthe fixator in an expanded configuration;

FIG. 19 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 20 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 21 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 22 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 23 is a diagrammatic view of a lead delivery device having apulley-like structure according to various embodiments of the presentteachings;

FIG. 23A is a diagrammatic view of a lead delivery device having apulley-like structure according to various embodiments of the presentteachings;

FIG. 24 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 25 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 26 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 27 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 28 is a detail of an environmental view of a lead delivery deviceaccording to various embodiments of the present teachings;

FIG. 29 is a sectional view of a lead with an internal attachment devicefor a lead delivery device according to various embodiments of thepresent teachings;

FIG. 30 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 31 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 32 is an environmental view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 33 is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 34A is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 34B is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 34C is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 35A is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 35B is a perspective view of a delivery shaft of the lead deliverydevice of FIG. 35A;

FIG. 36 is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 37A is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 37B is a cross-sectional view of a threaded nut of the leaddelivery device of the lead delivery device of FIG. 37A;

FIG. 37C is a perspective view of a threaded member of the lead deliverydevice of FIG. 37A;

FIG. 38A is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 38B is a perspective view of a shaft of the lead delivery device ofFIG. 38A;

FIG. 39 is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 40 is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 41 is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 42A is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIG. 42B is a perspective view of a lead delivery device according tovarious embodiments of the present teachings;

FIGS. 43-47B are perspective views illustrating various means ofremovably connecting a medical lead to a delivery shaft according to thepresent teachings;

FIGS. 48A and 48B are perspective views illustrating means of removablyconnecting a medical lead to a flexible member according to the presentteachings; and

FIGS. 49-53 are perspective views illustrating various means ofremovably connecting a medical lead to a delivery shaft according to thepresent teachings.

The drawings are not necessarily drawn to scale.

DESCRIPTION OF VARIOUS EMBODIMENTS

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, applications, or uses. Thepresent teachings are applicable to any devices that requireimplantation of electrically conductive leads, including pacemakers,defibrillators or other cardiac devices providing rhythm management,resynchronization therapy or other cardiac therapy.

During left heart (LH) lead delivery methods for implanting cardiactherapy devices, cannulated catheters can be used to provide support andstiffness and allow trackability of the lead into the coronary sinus andmore acute branching vessels. For example, in Cardiac ResynchronizationTherapy (CRT), a special third lead is implanted via the Coronary Sinus(CS) and positioned in a sub-selected cardiac vein to sense and/or pacethe left ventricle in combination with atrial-synchronized,biventricular pacing using standard pacing technology. Following asensed atrial contraction or atrial-paced event, both ventricles arestimulated to synchronize their contraction. The resulting ventricularresynchronization reduces mitral regurgitation and optimizes leftventricular filling, thereby improving cardiac function.

Guidewires can be used inside the Coronary Sinus and Great Cardiac Veinto gain access to acute side branches. A guidewire is placed into thetargeted vessel and the lead is placed over the guidewire and throughthe catheter. Under existing methods, during lead delivery, acompressive force is maintained by a forward pressure on both theguidewire and lead to allow the lead to travel distally in the branchingveins at the target site. The lead itself is designed to providestiffness and steerability characteristics for the purpose of placementinto the vessels. After the LH lead has reached its desired location,the delivery catheters used during the procedure must be removed byslitting because the proximal end of the lead is larger in diameter thanthe bore of the catheter and the catheter cannot be removed over thelead. The slitting procedure requires a very specific skill set,provides multiple avenues for user error and places constraints oncatheter design, construction and use.

In contrast to the existing method described above, the presentteachings provide a lead delivery device method that does not requireslitting the catheter. The lead delivery device includes a guidewirethat can be temporarily anchored in a sub-selected acute coronary veinbranch during lead delivery. Fixation can be provided by a fixator thatexpands from a compact configuration of very low profile fitting insidea lead to an expanded configuration having a dimension large enough toallow sufficient tension to be placed on the guidewire to enable leaddelivery over the guidewire in a zip-line or rope-climbing manner, asdescribed below. The guidewire with the fixator in the compactconfiguration can be guided through the catheter to the target site. Thecatheter can then be removed before the lead is advanced over theguidewire. After the lead is implanted, the fixator is returned to thecompact configuration and removed together with the guidewire throughthe implanted lead without slitting.

An exemplary lead delivery device 100 according to the present teachingsis illustrated during lead delivery of an electrically conductive lead200 in FIGS. 1, 1A and 1B. An implanted lead 200 is shown in FIG. 2,after the lead delivery device 100 is removed. The lead 200 can becannulated having an internal bore or lumen 204, a proximal portion 201,and a distal portion 202. The proximal portion 201 can be coupled with aconnector pin 207 to a connector block of a cardiac device 290, withwhich the lead 200 is in electrical communication. A catheter 250 havinga proximal end 252 and a distal end 254 can be used to insert the leaddelivery device initially through heart tissue 80, as shown in FIG. 1.

The lead delivery device 100 can include a guidewire 102 entering aproximal end 252 of the catheter 250 and exiting through a distal end254 of the catheter 250 as shown in FIG. 1. The guidewire 102 can besolid or cannulated with a bore 103, as shown in FIG. 12. The guidewire102 can include a distal portion 104 terminating in a tip 106. Thedistal portion 104 can be flexible for ease in guiding the guidewire 102through tortuous blood vessels to a target site 82, such as a branchingvein branching off the coronary sinus or other main blood vessel. Thelead delivery device 100 can include a fixator 150 coupled to theguidewire 102. The fixator 150 can assume an expanded or deployedconfiguration for anchoring the guidewire 102 near a target site 82during lead delivery and implantation, as shown in FIGS. 3, and 5-11,illustrating various fixator aspects. Referring to FIG. 1, the catheter250 can be removed by retracting the catheter 250 from heart tissue 80after the lead delivery device is anchored at the target site 82. Noslitting of the catheter 250 is required for removal of the catheter250. After the catheter 250 is removed, the lead 200 can be guided overthe guidewire 102 to the target site 82, as discussed further below.

The fixator 150 can be returned to a compact or undeployedconfiguration, such as the configuration illustrated in FIG. 4, forretracting and removing the guidewire 102 after lead delivery andimplantation. The maximum dimension, diameter or width of the fixator150 in the expanded configuration is denoted as L1 and in the contractedconfiguration as L2, as illustrated in FIGS. 3 and 4 for a fixator inthe form of a balloon.

FIGS. 5-11 illustrate various fixators 150 in their expandedconfiguration showing the maximum dimension L1 for each fixator 150. Thedimension L1 is selected to achieve a fixation force within a bloodvessel of an amount that allows the guidewire 102 to be pulled intension without being dislodged from the blood vessel while the lead ispushed over the guidewire 102, as discussed below. The fixation force Fcan be equal to or greater than about 2.24 N, or about 0.5 lbs, forachieving sufficient fixation within the blood vessel wall. The fixationforce F can generally be in the range of about 0.89 to 4.45 N (or 0.2 to1.0 lbs), depending on various factors, including the geometry of thebranching vessel. The deployed width or dimension L1 corresponding tothis fixation force F can be 5 mm, while the undeployed width ordimension L2 can be maintained to equal to or less than about 0.019inches, or about 0.483 mm, to allow easy passage through commerciallyavailable leads, such as those used with medical devices available fromMedtronic, Inc., of Minneapolis, Minn.

Referring to FIGS. 13-15, the distal portion 202 of an electrical lead200 is illustrated in connection with a guidewire 102 having a width L4and a fixator 150 having an undeployed width L2. The lead 200 isconductive and can deliver therapy in the form of electric energy at thetarget site 82. In one aspect, the lead 200 can also sense and relayinformation about electrical activity from the heart tissue 80 or targetsite 82 back to the cardiac device 290. The lead 200 can have aninternal bore or lumen 204, an internal coil or other conductive element210 and a tip portion 206 that can be an electrode tip with or without aseal. The tip portion 206 can define a distal opening 205 with width L3.In one aspect, the tip portion 206 can include a seal with flexibleflaps, not shown. The guidewire width L4 can be about 0.346 mm (or about0.014 inches) for providing steerability, stiffness and sufficientsupport for lead delivery over the guidewire 102.

The compact width L2 of the fixator 150 can be equal to or less than thewidth L3 of the distal opening 205, such that the fixator 150 can bepushed through the distal opening 205 in the direction C, as shown inFIG. 13. In one aspect the distal opening 205 can be offset relative toa central longitudinal axis of the lead 200, as shown in FIG. 16. Thefixator 150 can be deployed to the expanded configuration within theblood vessel 90 such that the expanded width L1 of the fixator 150 canpress against the internal lumen 92 of the blood vessel 90 with aholding force F, as discussed above, for temporarily anchoring theguidewire 102 into the blood vessel 90, as shown in FIG. 14.

Various fixators 150 can be used to temporarily and removably anchor theguidewire 102 in the lumen 92 of a blood vessel 90. Referring to FIGS. 3and 4, the fixator 150 can be a balloon having first and second ends111, 113 attached to the guidewire 102. The balloon can be inflated, forexample, with a gas or fluid, including a gel or other liquid, providedby a syringe through a valve 110 at a proximal end of the guidewire 102.In another aspect, a luer lock inflation port 120 can be coupled to theguidewire 102 for deploying the balloon. The balloon can be made from apolyblend material which is heated and stretched, placed around theguidewire 102 and bonded at first and second ends 111, 113 of theballoon onto the guidewire 102 with small amounts of cyanoacrylateadhesive, for example. A radio-opaque marker 108 in the form of a bandcan be placed adjacent the second (proximal) end 113 of the balloon forvisualization during guided navigation. The radio-opaque marker 108 canalso be in the form of a radio-opaque balloon coating or radio-opaquefluid filling the balloon. In another aspect, the balloon-type fixator150 can include an etched fixation surface with etched surface fixationformations 154 in the form of bumps, rings, etc., as illustrated inFIGS. 5 and 7. In another aspect, the fixator 150 can be a balloon withspiral or helical or otherwise curved configuration for maintaining apercentage of blood flow through the blood vessel 90 and aiding fixationin tortuous anatomy.

Referring to FIGS. 9-12, the fixator 150 can also be in the form of amechanical anchor with deployable straight wings 160, as shown in FIG.9, or curved wings 160, as shown in FIG. 10, or a pinwheel-type fixator150, as shown in FIGS. 11 and 11A. The mechanical anchor 150 can bedeployed with a longitudinal actuator 170 in the form of a wire orstring or other elongated member passing through the bore 103 of acannulated guidewire 102. Referring to FIG. 12, for example, the anchorwings 160 can pivot about a pivot pin 124 connected to the actuator 170and can be deployed to the expanded position in the direction of arrowsE by pulling the actuator 170 in the direction of arrow D.

In other aspects, the fixator 150 can be in the form of a superelasticwire, such as nitinol, and can be pre-shaped to expand to an anchorableconfiguration within the blood vessel 90.

In another aspect, fixators 150 including polymer lobes or superelasticor memory-shape wire can be used. Further, the dimensions of the fixator150, including the expanded width L1 and the compact width L2 can beselected to match the range of most common vessel sizes. The expandedshape of the fixator 150 can be selected to increase the contact areawith the blood vessel and or provide multiple contact surfaces forincreasing holding force and stability, as shown in FIGS. 6, 8, and 10,for example. The expanded shape can have a symmetric profile, as shownin FIG. 9, for example, or a non-symmetric profile, as shown in FIG. 6,for example. In other aspects, the expanded shape can have an asymmetricprofile for anchoring unidirectionally rather than bi-directionally.

As discussed above, deployment of the fixator 150 and anchoring canoccur after the cannulation of the coronary sinus CS with the catheter250 and after sub-selection of a side branch with the guidewire 102.Further, fixation of the guidewire 102 by the expandable fixator 150 canbe maintained during lead delivery and terminated after the lead 200 isdelivered to the target vessel at the target site 82. At the discretionof the operating physician, fixation and release can occur multipletimes during the medical procedure. Damage to the lead 200 duringfixation can be avoided because fixator expansion and fixation occursoutside the lead 200.

It should be appreciated, that according to the present teachings thelead delivery device 100 with either a balloon or mechanical fixator 150is configured and designed to function as a wedge or anchoring devicefor temporarily anchoring the guidewire 102 during the implantation ofthe electrical lead 200.

Referring to FIGS. 1-2, and 13-15, the cannulated catheter 250 can beinserted through heart tissue 80 into a coronary sinus CS, cardiac greatvein or other main vessel stopping short of a target site 82 that islocated in a sub-selected acute branching vessel 90. The guidewire 102with the fixator 150 in the undeployed compact configuration can beinserted through the catheter 250, advanced past the distal end 254 ofthe catheter 250 through a main vessel to the target site 82 in thebranching vessel 90, as shown in FIG. 1. The fixator 150 can then bedeployed and become anchored in the lumen 92 of the branching vessel 90with a holding force F, as discussed above. The catheter 250 can then beretracted and completely removed with no slitting procedure. The lead200 can be guided over the anchored guidewire 102 until the distalportion 202 of the lead 200 reaches the target site 82, as shown in FIG.1B. The lead 200 can be advanced by keeping the guidewire 102 in tensionwhile pushing the lead 200 in the direction of the fixator 150. When thedistal portion 202 of the lead 200 reaches the target site 82, thefixator 150 can be returned to its undeployed compact configuration andbe retracted through the lumen 204 of the lead 200, as shown in FIG. 15.The lead 200 can remain installed in the target site 82, as shown inFIG. 2, or advanced more distally in the branching vessel 90 beyond theoriginal target site 82 after the removal of the guidewire 102.

It will be appreciated that, in other aspects, the catheter 250 may beretained during the entire lead delivery procedure, such that the leadis inserted through the catheter 250 and over the guidewire 102, but insuch cases slitting of the catheter 250 may not be avoided after leadimplantation. In further aspects, the guidewire 102 and the lead 200 canbe inserted through the catheter 250 in any order, i.e., guidewire 102first, or lead 200 first or at the same time. In all aspects, however,the guidewire 102 can first be advanced to the target site 82 of abranching vessel 90 and the fixator 150 be deployed at the target site82. Only then the distal portion 202 of the lead 200 is advanced to thetarget site 82 by pushing the lead 200 over the guidewire 102 toward thetarget site 82, while the guidewire 102 remains fixed. Specifically, thelead 200 can be advanced to the target site 82 in a climbing-like or zipline-like manner by pulling and tensioning the guidewire 102 while theguidewire 102 remains anchored with the deployed fixator 150 at thetarget site 82.

Referring now to FIG. 17, a lead delivery device 300 according to someembodiments of the present disclosure is illustrated. Lead deliverydevice 300 comprises a guidewire 302 and fixator catheter 304. Guidewire302 may comprise a solid wire (as illustrated) or be cannulated, andincludes proximal portion 344 and distal portion 342. The fixatorcatheter 304 is a cannulated catheter comprising a tubular body 310 witha distal portion 320 and proximal portion 340. A fixator 312 is securedon the distal end 320 of fixator catheter 304. In FIGS. 17-22, fixator312 comprises an inflatable balloon, although any other form of fixatormay be utilized, as described above.

Guidewire 302 passes through fixator catheter 304 such that theguidewire 302 is encased within the tubular body 310 in at least aportion of the distal portion 320 of the fixator catheter 304. In theillustrated embodiments, this is accomplished by passing the distalportion 342 of the guidewire 302 through the body opening 316 of fixatorcatheter 304 such that it extends through the distal opening 314. Inthis manner, the guidewire 302 and fixator catheter 304 are incommunication at their distal portions 342, 320, while being separate attheir proximal portions 344, 340.

Referring now to FIG. 18, lead delivery device 300 is shown in thecondition where fixator 312 is expanded. In the illustration, fixator312 comprises an inflatable balloon that may be expanded by a gas orfluid, as described more fully above. In some embodiments, the tubularbody 310 of the fixator catheter 304 includes a lumen (not shown) thatis in communication with the inflatable balloon 312 and proximal end340. By providing a pressurized gas or fluid to the balloon 312, thefixator 312 is expanded to the expanded configuration. In the expandedconfiguration, the pressure inside balloon 312 will exert a force on acompressible or collapsible portion 313 of tubular body 310. In theillustrated embodiment, the compressible portion 313 is a portion of thelumen of the fixator catheter within the inflatable balloon, however,the compressible portion 313 may comprise a lumen of the balloon itselfor other arrangement. The force exerted by inflatable balloon 312 onportion 313 of tubular body 310 will cause that portion 313 to compressguidewire 302 such that guidewire 302 is secured to fixator catheter304. Portion 313 may be formed by providing a thinner wall in portion313 than is utilized in the remainder of tubular body 310.Alternatively, portion 313 may be formed of a different material thanthat used to form the rest of tubular body 310, or any other alternativestructure may be utilized (such as, adding a constrictive device orother securing mechanism). While the illustration in FIG. 18 shows aninflatable balloon 312 and a compressible or contract portion 313 oftubular body 310 to secure the guidewire 302 to fixator catheter 304,alternative structures and fixators may be substituted such that theguidewire 302 and fixator catheter 304 are secured together in theexpanded configuration, while remaining independently movable in thecompact configuration.

Referring now to FIGS. 19-22, a method for using lead delivery device300 to implant an implantable electrically conductive lead 360 within ablood vessel 350 is illustrated. Similar to FIG. 1, FIGS. 19-20 show thelead delivery device 300 utilized to implant implantable electricallyconductive lead 360 within the coronary sinus CS of heart tissue 80. Adelivery catheter 250 having a proximal end 252 and distal end 254 maybe utilized to assist in the delivery of guidewire 302 and fixatorcatheter 304 to a target or desired site 82. The fixator catheter 304,with guidewire 302 passed therein, is inserted through catheter 250 andnavigated to a position within the desired site 82. Upon delivery todesired site 82, fixator catheter 304 deploys its fixator 312 to secureguidewire 302 and fixator catheter 304 within blood vessel 350. In theexpanded configuration, fixator 312 exerts a force, as described above,upon the wall of blood vessel 350 sufficient to anchor both theguidewire 302 and fixator catheter 304 in the desired site 82 whiledelivery catheter 250 is removed and/or implantable electricallyconductive lead 360 is delivered to desired site 82, e.g., via guidewire302.

In the illustrations of FIGS. 19 and 20, delivery catheter 250 is shownas being present within the heart tissue 80 during delivery of lead 360.As shown in FIG. 19, in the expanded configuration fixator 312compresses or collapses portion 313 of fixator catheter 304 such thatguidewire 302 is fixedly secured within fixator catheter 304, asdescribed more fully above. Alternatively, as shown in FIG. 20,guidewire 302 may be removed from fixator catheter 304 before fixator312 is expanded. Fixator 312 may then be expanded to fixedly secureguidewire 302 between fixator 312 and the wall of blood vessel 350. Onceguidewire 302 is fixedly secured within blood vessel 350, implantableelectrically conductive lead 360 may be delivered to desired site 82 by,e.g., traveling over guidewire 302. With the guidewire 302 secured, therisk of the lead 360 being delivered incorrectly, i.e., outside ofdesired site 82, due to unintentional movement of guidewire 302 isreduced.

Once lead 360 is delivered to the desired site 82, the fixator 312 maybe contracted to a compact configuration (as shown in FIG. 17, forexample) and both guidewire 302 and fixator catheter 304 may be removedfrom desired site 82 and heart tissue 80. In some embodiments, fixator312 may be utilized to secure lead 360 against blood vessel wall 350while guidewire 302 is removed (see, e.g., FIG. 22). In this manner, itcan be ensured that there is no unanticipated movement of lead 360 fromdesired site 82 while guidewire 302 is removed from the patient's body.

Referring now to FIGS. 21 and 22, a method of finely adjusting theposition of guidewire 302 and lead 360 is illustrated. FIG. 21 showsfixator 312 in the expanded condition wherein guidewire 302 is securedbetween fixator 312 and the wall of blood vessel 350. This isaccomplished, for example, by delivering lead delivery device 300 to thedesired site 82 and then removing guidewire 302 from distal opening 314and body opening 316 of fixator catheter 304. The guidewire 302 may bepulled out of communication with fixator catheter 304 by pushing onfixator catheter 304 until the distal portion 342 of guidewire 302 ispulled out of and exits body opening 316. Then, guidewire 302 may bepushed past the distal portion 320 of fixator catheter 304, asillustrated. Fixator 312 may be expanded to secure guidewire 302 againstthe wall of blood vessel 350 and implantable electrically conductivelead 360 can then be navigated to desired site 82 by, for example,traveling over guidewire 302 through opening 364.

The position of implantable electrically conductive lead 360 andguidewire 302 may be finely adjusted with the selective use of fixatorcatheter 304. Fixator 312 may be expanded to secure guidewire 302 (asshown in FIG. 21) such that the position of lead 360 may be adjusted.Alternatively, as shown in FIG. 22, fixator catheter 304 may be movedsuch that fixator 312 is immediately adjacent the body of lead 360.Fixator 312 may then be expanded to secure lead 360 within blood vessel350. With lead 360 secured, the position of guidewire 302 may beadjusted without the possibility of moving lead 360. In this manner, auser may alternate between securing the guidewire 302 or lead 360 at acertain position, while adjusting unsecured lead 360 or guidewire 302,respectively, and thus more accurately and simply adjust the positioningof lead 360 within desired site 82.

Referring to FIGS. 23-32, a lead delivery device 400 and associatedmethods are illustrated according to various exemplary embodiments. Thelead delivery device 400 can employ a method similar to pulley orflagpole principle to advance the lead using a pulley or pulley-likestructure.

An exemplary embodiment of the lead delivery device 400 is illustratedin FIGS. 23 and 23A largely diagrammatically. The lead delivery device400 can include a delivery shaft 402 having an inner passage or lumen420, a fixator/fixation device 404 for temporary fixation during leaddelivery and an electrically conductive medical lead 406 for animplantable medical device 290 (shown in FIG. 2). The medical lead 406can have first and second ends 424, 426. The lead delivery device 400can include a pulley structure 408 and an elongated flexible member 410,such as a string, rope or cable, having a first portion 412 and a secondportion 414. The flexible member 410 can pass through the inner passage420, change direction over or around the pulley structure 408 and passthrough a lumen 422 of the lead 406, such that the flexible member 410takes a U-shape by a U-turn at the pulley structure 408, as shown inFIG. 23. Pulling the first portion 412 of the flexible member 410 in thedirection A moves the lead 406 in the direction B. A retainer, such as aknot, a button-like plate, a ball or a rod or other attachment device416 can be at least temporarily coupled to the flexible member 410 andused as a stop to keep the lead 406 coupled onto the flexible member 410as the flexible member 410 is pulled in the direction A away from hearttissue 80 to force the lead 406 to follow along the path of the flexiblemember 410.

Alternatively, as shown in FIG. 23A, the flexible member 410 can remainoutside the delivery shaft 402 and outside the lead 406. The flexiblemember 410 can be coupled to the delivery shaft 402 with one or moreexternal retainer elements 417, such as, for example, resilient rings,loose adhesive tape, easily breakable spot adhesive, or other devicesthat allow movement of the flexible member 410 relative to the deliveryshaft 402, while maintaining coupling with the delivery shaft 402.Similarly, the flexible member 410 can be coupled to the lead 406 withone or more external retainer elements 417, or with one or moreretainers 419 positioned adjacent to the distal end 424 of the lead 406.The retainer 419 can be an attachment made by a dissolvable adhesive orby various other means, as discussed below. In various embodiments, theattachment can be made by electrical or thermal fusing. In variousembodiments, the retainer 419 can include an electrical fuse such thatpassing a specified electrical current through the flexible member 410can cause the electrical fuse to blow/break and release the flexiblemember 410 from the lead 406. A delivery shaft 402 and lead 406 ofsmaller diameter can be used when the flexible member 410 remainsoutside the delivery shaft 402 and the lead 406. It will be appreciatedthat the flexible member 410 need not extend along the entire length ofthe lead 406. The flexible member 410 can terminate, for example, at thelocation of the retainer 419, or the retainer 417, if used.

In various embodiments, the delivery shaft 402 can be made of abiocompatible material, such as, for example, a metallic or polymeric orother material. The delivery shaft 402 can also be a tubular catheter402 a or a tubular guidewire 402 b or a solid guidewire 402 c or otheranchoring wire, as is discussed below in connection with FIGS. 24, 25and 30-32. The lead 406 can travel along a path substantially paralleland adjacent to the shaft 402, either outside the passage 420 of theshaft 402, as illustrated in FIG. 23, or within the shaft passage 420.The flexible member 410 can be metal, polymer, string, plastic, hybridof materials or can be made of different materials along the length ofthe flexible member 410.

The pulley structure 408 can be a pulley of appropriate size, such as amicro-machined pulley, or a 180-degree corner or U-turn in the deliveryshaft 402 or outside the deliver shaft 402. In some embodiments, thepulley structure 408 can be formed by passing the flexible member 410through first blood vessel 90 and exiting through a second blood vessel90 forming a U-turn loop. Various exemplary embodiments are discussedbelow.

The fixator 404 can be an inflatable balloon, an expandable anchor, adistal portion of a catheter or guidewire that can be wedged in a smallblood vessel because of its size, surface texture, friction, shape,properties, etc. The fixator 404 can also be selected from variousfixators described herein above, such as fixators 150 or 312.

In various embodiments, the lead delivery device 400 can include a shaft402 in the form of a flexible deformable catheter 402 a, such as thefixator catheter 402 a illustrated in FIG. 24. The catheter 402 a orshaft 402 can be a hollow tubular member and can include a distal end430 and a proximal end 432. In FIG. 24 the lead delivery device 400 isutilized to guide the lead 406 through the coronary sinus osteum 84 ofheart tissue 80. The distal end 430 of the catheter 402 a can bedeformed to a U-shape within the blood vessel 90 and can function bothas a fixator 404 and as a pulley structure 408 for delivering the lead406, as is also illustrated in FIG. 27. Pulling the first portion 412 ofthe flexible member 410 in the direction A moves the lead 406 along theflexible member 410 in the direction B substantially parallel to thecatheter 402 a through coronary sinus osteum 84 until the first end 424of the lead 406 reaches the target site 82. The flexible member 410 canthen be removed by pulling at portion 414 in the opposite direction ofarrow B. The catheter 402 a can be removed by pulling the proximal end432 away from the patient in the direction of arrow A.

In various embodiments, the lead delivery device 400 can include a shaft402 in the form of a flexible deformable guidewire 402 b, as illustratedin FIG. 25. The guidewire 402 b can be a hollow tubular member,generally of smaller diameter than the catheter 402 a. In FIG. 25, thefixator 404 is illustrated as an expandable member, such as a balloon.The flexible member 410 can pass through the lumen of the guidewire 402b and form a U-turn at pulley structure 408, which can be any one of thepulley structures discussed above, including an opening in the fixator404. In various embodiments, the guidewire 402 b itself can function asboth the delivery shaft 402 and the flexible member 410 with the fixator404 removably attached to the unitary guidewire/flexible member, suchthat it remains at the target site 82 when the guidewire/flexible memberis removed.

With continued reference to FIG. 25, pulling the first portion 412 ofthe flexible member 410 in the direction A moves the lead 406 along theflexible member 406 in the direction B substantially parallel to theguidewire 402 b through coronary sinus osteum 84 until the first end 424of the lead 406 reaches the target site 82. The flexible member 410 canthen be removed by pulling at portion 414 in the opposite direction ofarrow B. The guidewire 402 b can be removed by pulling the proximal end432 away from the heart tissue 80 in the direction of arrow A.

In various embodiments, the lead delivery device 400 can include a shaft402 having a distal portion 405 with stiffness and width configured toform a fixator 404 by frictional attachment to the blood vessel 90, asillustrated in FIG. 26. In the illustrative embodiment of FIG. 26, thepulley structure 408 is a hole through which the flexible member 410exits the delivery shaft 402, makes a U-turn and passes through thelumen of the lead 406.

In various embodiments, a portion 410 a of the flexible member 410 caninclude a coiled portion 410 a coiled around a portion of the deliveryshaft 402 between the distal end 424 of the lead 406 and a distal end430 of the shaft 402, as illustrated in FIG. 28. The coiled portion 410a can keep the lead 406 close to the delivery shaft 402 as the lead 406is moved along the shaft 402. The coiled portion 410 a moves intranslation with the lead 406 and unravels as the flexible member entersthe passage 420 of the delivery shaft 402 at the distal end 430 of thedelivery shaft 402 where the flexible member 410 forms the pulleystructure 408 by a U-turn.

In various embodiments, the various retainers 416, 417, 419 describedabove can be coupled to the flexible member 410 outside the lead 406, asshown in the exemplary illustrations of FIGS. 23-25. In variousembodiments, the retainer 416 can be coupled to the flexible member 410within the lumen 422 of the lead 406, as illustrated in FIG. 29. Theretainer 416 can be, for example, a knot in the flexible member 410, ametallic or polymer device, a wedge, an inflatable device, a deformabledevice, or an expandable basket. The retainer 416 can be temporarilyshapeable or can be made of a memory-shaped device. The retainer 416 canalso be a threaded screw or a device held in the lumen 422 of the leadby compression fit. The retainers 416, 419 can be attached to flexiblemember 410 and/or the lead 406 by electrical connection, by adhesive, bythermal connection (heating or freezing). The retainers 416, 419 can bedetached and disconnected by softening an adhesive, by dissolving, byelectrically breaking a fuse embedded in the retainer as described abovein connection with retainer 419, by mechanical force to overcome theattachment force, such as by breaking the flexible member 410 or aportion of the lead 406, or by deforming, deflating, or breaking theretainer 416. A section of reduced width or a section weakened with anotch or other frangible feature 440 may be provided at selectedlocation. In various alternative embodiments, the retainer 416 can beremoved by pulling the flexible member 410 in a direction opposite tothe direction B, as shown in FIGS. 24 and 25.

In various embodiments, the fixator 404 can be attached to a distalportion of the guidewire 402 b or the catheter 402 a as illustrated invarious embodiments of FIGS. 30-32 (dimensions not in scale).

Referring to FIG. 30, for example, the guidewire 402 b can include afixator 404 attached to the distal portion 452 of the guidewire 402 bfor anchoring into the lumen 92 of a blood vessel 90. The guidewire 402b can include a guidewire lumen 442 with a side opening 454 that formsthe pulley structure 408 The flexible member 410 can pass though theguidewire lumen 442, out of the side opening 454 and around the pulleystructure 408 and extend between the guidewire 402 b and the lumen 92 ofthe blood vessel 90. In various embodiments, the guidewire 402 b can bepre-loaded with the flexible member 410. Once the guidewire 402 b ispositioned and fixated in the blood vessel 90, the lead 406 can beattached to the flexible member 410. Pulling the flexible member 410 inthe direction A advances the lead 406 in the direction B.

Referring to FIG. 31, the fixator 404 can be attached to the catheter402 a. The catheter 402 a can include a first lumen 446 with a sideopening 456 that forms the pulley structure 408. The flexible member 410can pass though the first lumen 446, out of the side opening 456 andaround the pulley structure 408 and extend between the catheter 402 aand the lumen 92 of the blood vessel 90. A relatively small diameterhollow or solid guidewire 402 c can pass through a second lumen 448through the fixator 404 for guiding the catheter 402 a. Once thecatheter 402 a is positioned and fixated in the blood vessel 90, thelead 406 can be attached to the flexible member 410. Pulling theflexible member 410 in the direction A advances the lead 406 in thedirection B.

Referring to FIG. 32, the fixator 404 can be attached to the catheter402 a. The catheter 402 a can include a lumen 450 having a side opening456 that forms the pulley structure 408. The lumen 450 can include afirst or proximal lumen portion 451 and a second or distal lumen portion453. The second lumen portion 453 can pass through the fixator 404. Theflexible member 410 can pass though the first lumen portion 451, out ofthe side opening 456 and around the pulley structure 408 and can extendbetween the catheter 402 a and the lumen 92 of the blood vessel 90. Asmall diameter hollow or solid cross-section guidewire 402 c can extendthrough the first lumen portion 451 and the second lumen portion 453 forguiding the catheter 402 a. The guidewire 402 c can be first positionedin the blood vessel 90 and the catheter 402 a pre-loaded with theflexible member can be positioned over the guidewire 402 c. Pulling theflexible member 410 in the direction A advances the lead 406 in thedirection B. Alternatively, the guidewire 402 c can pass through theside opening 456 only though the second lumen portion 453, as shown inphantom line.

The various embodiments described above in connection with FIGS. 23-32facilitate the implantation of a lead 406 using a pulley structure 408and allow the physician to deliver the lead 406 to a target site by apulling action rather than pushing. Because pulling a thin elongatedmember through a curved lumen can avoid buckling, kinking or otherconvolutions that may occur when pushing is used instead, a leaddelivery device 400 using a pulley structure can utilize smallerdiameters or reduced stiffness for the lead as well as the cathetersand/or guidewires.

Referring to FIGS. 33-37C, a lead delivery device 500 and associatedmethods are illustrated according to various exemplary embodiments. Thelead delivery device 500 is similar in certain respects to the leaddelivery device 400 described above. Structural elements that aregenerally common or equivalent between the lead delivery devices 400 and500 are denoted by numerals sharing the second and third digits. Forexample, the electrically conductive medical lead is referenced by thenumeral 506 for the lead delivery device 500.

In various embodiments, the lead delivery device 500 can employ a pushmethod for advancing the lead without using a pulley-like structure toadvance the lead. In various embodiments, the lead delivery device 500can employ a lead advancement member 562 that functions as a guidingrail or a pusher for pushing the medical lead over a delivery shaft tothe target site, as discussed below in connection with FIGS. 33-37C. Invarious other embodiments, the lead delivery can include hydraulicpressure or vacuum suction with or without a pulley structure to advancethe lead, as discussed below in connection with FIGS. 38A-42B.

An exemplary embodiment of the lead delivery device 500 is illustratedin FIG. 33 largely diagrammatically. The lead delivery device 500 caninclude a delivery shaft 502, a fixator/fixation device 504 fortemporary fixation during lead delivery and an electrically conductivemedical lead 506 for an implantable medical device 290 (shown in FIG.2). In various embodiments, the delivery shaft 502 can be an elongatedmember, such as, for example, a catheter or a guidewire either with orwithout an inner fixator lumen 520. The medical lead 506 can have eithera solid body or a cannulated body with an internal lead lumen 522 andfirst and second ends 524, 526. The medical lead 506 can be coupled tothe delivery shaft 502 with a lead advancement member 562 which can bein the form of a stiff wire or a substantially rigid guiding rail or aflexible member referenced as 510, such a string, thread or thin wire,or a combination thereof. The flexible member 510 can include first andsecond end portions 512, 514. In the embodiment of FIG. 33, the flexiblemember 510 can pass through the lead lumen 522 of the medical lead 506and be attached at the second end portion 514 by an attachment device,such as, for example, by looping and tying the second end portion 514around the delivery shaft 502 forming a connector 560, such as, forexample, a loop or ring 560 around the delivery shaft 502. Once thedelivery shaft 502 is anchored via the fixator 504 in the target cardiacsite, the medical lead 506 can be pushed along and over the flexiblemember 510 in the direction of arrow D. The flexible member 510 can bekept taut by applying tension at the first (proximal) portion 512 in thedirection of arrow T (opposite to the direction D). When a stiff guidingrail is used for the lead advancement member 562 in place of theflexible member 510, the medical lead 506 can be pushed over the leadadvancement member 562 without tensioning. The fixator 504 can bedetached, for example, by deflating or un-deploying the fixator 504. Thedelivery shaft 502 with the flexible member 510 can then be removed bypulling in the direction T away from the target site.

With further reference to FIG. 33, the lead advancement member 562 canbe permanently or temporarily attached to the delivery shaft 502. Thelead advancement member 562 can be flexible, similar to a floppy string,and able to easily attach to the delivery shaft 502. The leadadvancement member 562 can have a connector 560 with a preformed shapeon its distal portion 514 and may attach to the delivery shaft 502without collapsing the inner lumen 520 of the delivery shaft 502. Inother embodiments, the lead advancement member 562 can be attached tothe delivery shaft 502 by crimping or by adhesive. A piece of heatshrink may also be placed over the lead advancement member 562 to secureit to the delivery shaft 502. A groove may be cut into the deliveryshaft 502 to better place the lead advancement member onto the deliveryshaft.

The lead advancement member is able to be loaded through or onto amedical lead by having a stiff portion, like a stylet wire, attached toits proximal end for threading through lead. This proximal portion ofthe lead advancement member may then be removed, by cutting forinstance, after successfully loading the lead. The lead advancementmember could be a stand alone product to be used or paired with anyavailable common delivery shaft.

In various embodiments, and referring to FIGS. 34A-34C, a separateguiding rail or an elongated lead advancement member 562 can be used topush the medical lead 506 along the delivery shaft 502. The leadadvancement member 562 can be a wire or other relative stiff or rigidmember coupled to delivery shaft 502 with a connector, which can be anintegral external eyelet or ring 560 which is slidably disposed aroundthe delivery shaft 502. The lead advancement member 562 can be pushed inthe direction of arrow D, pushing the connector or ring 560 and themedical lead 506 toward the target site along the same direction D. Invarious embodiments, the medical lead 506 can be coupled to the leadadvancement member 562 or the ring 560 by a flexible member 510 thatextends between a retainer 519 adjacent to the distal end 524 of themedical lead 506 and the ring 560 or a portion of the lead advancementmember 562 adjacent to the ring 560, as illustrated in FIG. 34A. Theretainer 519 can be any of the types of retainer described above andsimilar to the retainer 419 of the lead delivery device 400 illustratedin FIG. 23A. In other embodiments, and as illustrated in FIG. 34B, theflexible member 510 can pass through the lead lumen 522 and can becoupled to the medical lead 506 by a retainer 516, similar to theretainer 416 discussed above in connection with FIG. 23. In otherembodiments, and as illustrated in FIG. 34C, the flexible member 510 canremain outside the medical lead 506 and can be coupled loosely to themedical lead 506 by retainers 517 or 519, similar to the retainers 417and 419 discussed above in connection with FIG. 23A. Additional means ofremovably connecting the medical lead 506 to the delivery shaft 502 orthe flexible member 510 are illustrated in FIGS. 43-53 and are describedbelow.

In various embodiments, and referring to FIGS. 35A and 35B, the leaddelivery device 500 can include an elongated lead advancement member 562that is slidably received in a delivery lumen 521 of the delivery shaft502. The delivery lumen 521 can be open to the outer surface of thedelivery shaft 502 forming an open channel that communicates with anexternal longitudinal slot 523 for connection with the medical lead 506via the flexible member 510. The open delivery lumen 521 can be aseparate lumen and non-communicating with a fixator lumen 520 which isused for deploying the fixator 504, such as for inflating a balloon-likefixator 504, for example. The medical lead 506 can be advanced in thedirection of the arrow D by pushing the lead advancement member 562along the delivery lumen 521 in the same direction D.

Referring to FIG. 36, the lead advancement member 562 can include adistal magnetized/magnetic portion 564 that can interact magneticallywith a magnetized/magnetic eyelet or ring 560. The ring 560 can becoupled to the distal end 524 of the medical lead 506 via a flexiblemember 510. The ring 560 can be slidably disposed externally around thedelivery shaft 502. Magnetic interaction can advance the medical lead506 in the direction D, while the lead advancement member 562 is pushedin the direction D inside a closed delivery lumen 521 of the deliveryshaft 502. The magnetic portion 564 and the magnetic ring 560 caninteract by repulsive magnetic forces (similar magnetic polarity) suchthat the ring 560 moves ahead of the magnetic portion 564 as thedelivery shaft 502 advances in the direction D. Alternatively, themagnetic portion 564 and the magnetic ring 560 can interact byattractive magnetic forces (opposite magnetic polarity), such that thering 560 moves together with the magnetic portion 564 as the deliveryshaft advances in the direction D.

Referring to FIGS. 37A, 37B and 37C, the lead advancement member 562 canbe in the form of a threaded elongated member, which is threadablyconnected to an inner threaded lumen 567 of a nut 566. The nut 566 caninclude an anti rotation feature, such as tab 568 that extends outsidethe open delivery lumen 521 through an external slot 523. Rotating theadvancement member 562 in the direction of the curved arrow E causes thenut 566 to slide along the delivery shaft 502 in the direction of arrowD. The medical lead 506 can be coupled to the nut 566 and move along thedelivery shaft 502 together with the nut 566. The medical lead 506 canbe coupled to the nut 566 with any of the various connections discussedabove. For example, the medical lead 506 can be connected to the tab 568with a flexible member 510 directly connected to the tab 568. Theflexible member 510 can be indirectly connected to the tab 568 bymagnetic forces between a magnetized portion of the tab 568 and amagnetized portion of an external ring 560 around the delivery shaft502, with the ring 560 coupled to the flexible member 510, as describedin connection with FIG. 36.

Referring to FIGS. 38A-39, the lead advancement member can be in theform of hydraulic pressure p exerted on a hydraulic plug 570 coupled tothe medical lead 506. In FIG. 38A, for example, the flexible member 510is coupled to and extends between the medical lead 506 and a tab 572that extends from the hydraulic plug 570 and protrudes through thelongitudinal slot 523 of the delivery lumen 521 of the delivery shaft502. Hydraulic pressure p can be provided through the flow of a liquidmedium, including blood or a saline solution. The delivery lumen 521 andthe longitudinal slot 523 can include a sealing structure 525 forreducing leakage of the liquid. For example, the delivery shaft 502 caninclude a sealing structure 525 in the form of an extension under theslot 523, such that communication between the longitudinal slot 523 andthe delivery lumen 521 is redirected to a small opening 523 a under andat an offset from the opening of the longitudinal slot 523, as shown inFIG. 38B. In other embodiments, the sealing structure 525 can be aflexible flap or hydraulic valve or other sealing member that openssufficiently to allow the passage of the tab 572 to pass and closesbehind the tab 572 to reduce leakage through the longitudinal slot 523of the delivery shaft 502. Under the effect of the hydraulic pressure,the hydraulic plug 570 and the medical lead 506 move in the direction ofarrow D toward the target site.

In other embodiments, as illustrated for example in FIG. 39, thedelivery lumen 521 can have a closed-channel cross-section. Magneticcoupling can be used between the hydraulic plug 570 and an external ring560 slidably surrounding the delivery shaft 502 and coupled to themedical lead 506 via a flexible member 510, as also described inconnection with FIG. 36. Under the effect of the hydraulic pressure p,the hydraulic plug 570 and the medical lead 506 can move in thedirection of arrow D toward the target site. Venting can be provided bya vent 590 that passes through the fixator 504 or through other locationproximal to the fixator 504.

In various embodiments, as illustrated for example in FIG. 40, hydraulicpressure p can be used with a pulley structure 508 to advance themedical lead 506 in the direction of arrow D toward the target site(away from the physician). The pulley structure 508 can be attached tothe delivery shaft 502 with a support element 509, such as a rod. Thedelivery shaft 502 can include first and second delivery lumens 521 aand 521 b. The first and second delivery lumens 521 a and 521 b can beseparate lumens that communicate at a U-shaped junction 574 at theirdistal ends. Hydraulic pressure p can be applied through the seconddelivery lumen 521 b in the direction of arrow D. The hydraulic liquidpasses through the U-shape junction 574 and exerts pressure on thehydraulic plug 570 in the direction A, opposite to the direction D,along the first delivery lumen 521 a. The hydraulic plug 570 can becoupled to the medical lead 506 via a flexible member 510 which changesdirection making a U-turn as the flexible member 510 passes by a pulleystructure 508, similar to the pulley structures 408 described above inconnection with the lead delivery system 400. The flexible member 510can be coupled to the hydraulic plug 570 through a gasket, a valve orother sealing member 580 to minimize leakage at the entry into the firstdelivery lumen 521 a. As the hydraulic pressure p pushes the hydraulicplug 570 in the direction A, the medical lead advances in the directionD toward the target site (away from the physician).

Hydraulic vacuum suction (negative pressure) “ps” can be used with apulley structure 508 to advance the medical lead in the direction ofarrow D toward the target site (away from the physician), as illustratedin FIG. 41. The medical lead 506 can be coupled to a flexible member510, which passes by a pulley structure 508 and is coupled to thehydraulic plug 570 through an opening or vent 590. When suction ps isapplied in the direction A, which is opposite to the direction D, thehydraulic plug 570 can move in the direction A, while the medical lead506 moves in the direction D. Leakage during lead delivery can beavoided by using suction.

Referring to FIGS. 42A and 42B, hydraulic pressure p can be applieddirectly to the medical lead 506 to advance the medical lead 506 in thedirection D toward the target site. The medical lead 506 can be insertedin the delivery lumen 521 and pressure p can be applied through thedelivery lumen 521 against an enlarged head portion 506 a of the medicallead 506, as shown in FIG. 42A. To limit leakage of the hydraulic fluid,pressure p can be applied through a side port or side opening 584 of thedelivery shaft 502. A gasket or a valve or other sealing member 580 withflexible flaps 582 can be used proximally to the side opening 584 tolimit leakage around the medical lead 506 at the proximal end of thedelivery shaft 502. Venting can be provided by a vent 590 that passesthrough the fixator 504 or through other location proximal to thefixator 504.

Referring to FIGS. 43-53, various exemplary means for removablyconnecting the medical lead 506 to the delivery shaft 502 or to aflexible member are illustrated. The lead attachment/detachment meansillustrated in these figures can be used interchangeably in any of theembodiments described above such that the medical lead 506 can beremovably connected to the delivery shaft 502 or to the flexible member510.

Referring to FIG. 43, the medical lead 506 can be connected to thedelivery shaft 502 using a removable connection similar to chain lock ona door. The delivery shaft can include a keyhole-shaped slot 592including a longitudinal slot 596 and an enlarged opening 594 that iswider than the longitudinal slot 596. The first end 512 of the flexiblemember 510 is attached to the medical lead 506 and the second end 514 toa pin or disk 600 which can be inserted in and removed from the slot 592through the enlarged opening 594, as shown in FIG. 43. The position ofthe flexible member 510 with the disk 600 during attachment or removalfrom the slot 592 of the delivery shaft 502 is shown in phantom line. Inexemplary illustration of FIG. 43, the medical lead 506 is moved bypushing the delivery shaft 502 in the direction D.

Referring to FIG. 44, the lead advancement member 562 includes a pin630, which is attached to the ring 560 at an intermediate pin portionbetween the ends of the pin 630. The ring 560 can slide over thedelivery shaft 502, as described above. The first end 512 of theflexible member 510 is attached to the medical lead 506 and the secondend includes a loop 632 that slides over the pin 630. The loop 632 isheld by the pin 630 when the lead advancement member 562 is pushedtoward the target site in the direction D, and slides off the end of thepin 630, when the lead advancement member 562 is retracted in theopposite direction away from the target site.

Referring to FIG. 45, an outer catheter 602 having a sharp distal tip603 can be slid over the lead advancement member 562 and the deliveryshaft 502 to cut the flexible member 510 after the medical lead 506 hasreached the target site.

Referring to FIG. 46, the ring 560 on the lead advancement member issized so that the ring 560 can push against the head 506 a of themedical lead 506 to push the medical lead 506 along the delivery shaft502 toward the target site. Once the medical lead 506 is delivered tothe target site, the lead advancement member 562 can be pulled off themedical lead 506 in the opposite direction. The connections illustratedin FIGS. 47A and 47B operate similarly, except that the ring can be inthe form of a corkscrew-like ring 563. The corkscrew-like shape canfacilitate loading the delivery shaft 502 and the medical lead 506 intothe lead advancement member 562. The lead advancement member 562 can beremoved either by pulling back in the direction opposite to thedirection of delivery, direction D or by a rotating or unscrew-type ofmotion. The corkscrew ring 563 illustrated in FIG. 47B can be sized tobe wrapped around the delivery shaft 502 more tightly, and have atighter pitch, such that slight flexing of the corkscrew ring may berequired for loading/unloading the medical lead 506 through thecorkscrew-like ring 563. The corkscrew-like ring can be made of flexibleelastically deformable material or shape-memory material, such asstainless steel wire, plastic material or nitinol, for example.

Referring to FIGS. 48A and 48B, a connection similar to the connectionof FIG. 43 discussed above can used between the medical lead 506 and theflexible member 510. The medical lead 506 can include an external pocket610 attached on an outer surface of the medical lead 506 adjacent to thehead 506 a. The pocket 610 defines an interior receptacle 615 withproximal open end 611 and a closed distal end 613. The pocket 610includes a longitudinal narrow slot 612 that communicates with theinterior receptacle 615. The proximal end 512 of the flexible member 510can be attached to a pin or disk 614 which is received in the interiorreceptacle 615 with the proximal end 512 of the flexible member 510extending through the slot 612 outside the pocket 610. Pulling theflexible member 510 in the direction of arrow B moves the medical lead506 in the same direction B for delivery to the target sites, as shownin FIG. 48A. Pulling the flexible member 510 in the direction of arrow Amoves the disk 614 out of the interior receptacle 615 of the pocket 610and releases the flexible member 510. It is appreciated that theflexible member 510 can be attached to the lead advancement member 562or the delivery shaft 502 in the manner described in any of theembodiments discussed above, in which the distal end of the flexiblemember 510 is coupled to the lead advancement member 562 or to thedelivery shaft 502.

Referring to FIG. 49, the medical lead 506 can be attached to the leadadvancement member 562 with a flexible clip 616. After the medical lead506 has been delivered to the target site, the clip 616 can be removedby pushing the lead advancement member 562 forward in the direction D,while holding the medical lead 506 stationary, such that the clip 616 ispulled over and off the head 506 a of the medical lead 506.

Referring to FIG. 50, the head 506 a of the medical lead 506 can beplaced into an elastic cap or other elastic enclosure 620 that isattached to the lead advancement member 562. After the medical lead 506has been delivered to the target site, the elastic enclosure 620 can beremoved by pushing the lead advancement member 562 forward in thedirection D, while holding the medical lead 506 stationary, such thatthe elastic enclosure 620 is pulled off the head 506 a of the medicallead 506.

Referring to FIG. 51, the head 506 a of the medical lead 506 can beplaced into a braided mesh or braided and open ended enclosure 622 thatis attached to the lead advancement member 562. The braided enclosure622 can take a shape with a narrower diameter when in tension and aloose-fitting shape of larger diameter under compression. When themedical is being delivered to the target site, the braided enclosure 624s in tension and holds the head 506 a of the medical lead 506. After themedical lead 506 has been delivered to the target site, the braidedenclosure 624 an be removed by holding the medical lead 506 stationaryand pulling the lead advancement member 562 in the direction A toaxially compress the braided enclosure 624 such the medical lead 506 canbe pulled free and out of the loosened braided enclosure 624.

Referring to FIG. 52, the medical lead 506 can includes a distal activefixator in the form of a screw or helix 507. For delivery to the targetsite, the helix 507 can be removably screwed into a receptacle 626 whichis attached to the lead advancement member 562. After the medical lead506 has been delivered to the target site, the helix 507 can beunscrewed from the lead advancement member 562, which is then removed.The helix 507 can be screwed to cardiac tissue for active fixation ofthe medical lead 506.

Referring to FIG. 53, the medical lead 506 can include a distal passivefixator in the form of compressible/expandable tines 509. For deliveryto the target site, the tines 509 can be compressed into a receptacle628 which is attached to the lead advancement member 562. After themedical lead 506 has been delivered to the target site, the receptacle628 can be removed by pushing the lead advancement member 562 forward inthe direction D, while holding the medical lead 506 stationary, suchthat the receptacle 628 is pulled off the medical lead 506 and the tines509 expand for passive fixation.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. Furthermore, the mixing andmatching of features, elements and/or functions between variousembodiments is expressly contemplated herein, so that one of ordinaryskill in the art would appreciate from this disclosure that features,elements and/or functions of one embodiment may be incorporated intoanother embodiment as appropriate, unless described otherwise above.Moreover, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. One skilled in the art will readily recognizefrom such discussion, and from the accompanying drawings and claims,that various changes, modifications and variations can be made thereinwithout departing from the spirit and scope of the present teachings asdefined in the following claims.

1. A method of delivering a medical lead to an anatomic target site, themethod comprising: inserting a hydraulic plug into an internal deliverylumen of a delivery shaft, the delivery shaft insertable to the targetsite; coupling a medical lead to the hydraulic plug; applying hydraulicpressure to the hydraulic plug through the delivery lumen; moving thehydraulic plug toward the target site; and advancing the medical leadtoward the target site.
 2. The method of claim 1, wherein coupling amedical lead to the delivery plug includes connecting a flexible memberbetween the medical lead and a tab of the hydraulic plug, the tabprotruding through an external longitudinal slot of the delivery shaft.3. The method of claim 1, wherein coupling a medical lead to thedelivery plug includes: coupling a flexible member between a distal endof the medical lead and an external ring surrounding the lead deliveryshaft; and magnetically coupling the external ring with the hydraulicplug.
 4. A method of delivering a medical lead to an anatomic targetsite, the method comprising: inserting a hydraulic plug into a firstinternal delivery lumen of a delivery shaft, the delivery shaftinsertable to the target site; coupling a medical lead to the hydraulicplug; applying hydraulic pressure to the hydraulic plug through a secondinternal delivery lumen separate from and substantially parallel to thefirst delivery lumen and communicating with the first delivery lumenthrough a U-shaped junction; moving the hydraulic plug; and advancingthe medical lead toward the target site.
 5. The method of claim 4,wherein coupling a medical lead to the hydraulic plug comprises:connecting a flexible member to a distal end of the medical lead;passing the flexible member by a pulley structure; and connecting theflexible member to the hydraulic plug.
 6. The method of claim 5, whereinmoving the hydraulic plug includes moving the hydraulic plug in adirection away from the target site.
 7. A method of delivering a medicallead to an anatomic target site, the method comprising: inserting ahydraulic plug into an internal delivery lumen of a delivery shaft, thedelivery shaft insertable to the target site; coupling a medical lead tothe hydraulic plug; applying vacuum suction to the hydraulic plugthrough the delivery lumen; moving the hydraulic plug; and advancing themedical lead toward the target site.
 8. The method of claim 7, whereincoupling a medical lead to the hydraulic plug comprises: connecting aflexible member to a distal end of the medical lead; passing theflexible member by a pulley structure; and connecting the flexiblemember to the hydraulic plug.
 9. The method of claim 8, wherein movingthe hydraulic plug includes moving the hydraulic plug in a directionaway from the target site.
 10. A method of delivering a medical lead toan anatomic target site, the method comprising: inserting a medical leadinto an internal delivery lumen of a delivery shaft, the delivery shaftinsertable to the target site; applying hydraulic pressure to anenlarged distal portion of the medical lead; and advancing the medicallead toward the target site.
 11. The method of claim 10, whereinapplying hydraulic pressure to an enlarged distal portion of the medicallead comprises applying pressure through a side opening of the deliveryshaft, the side opening communicating with the delivery lumen.
 12. Themethod of claim 11, further comprising sealing a proximal end of thedelivery lumen.
 13. A lead delivery device comprising: a medical lead;an elongated delivery shaft insertable to an anatomic target site of apatient, the delivery shaft having a longitudinal delivery lumencommunicating with an open longitudinal slot of the delivery shaft; ahydraulic plug slidably received in the delivery lumen; and a flexiblemember coupling the medical lead to the hydraulic plug through the openslot, such that pressure exerted to the hydraulic plug through thedelivery lumen advances the hydraulic plug and the medical lead towardthe target site.
 14. The lead delivery device of claim 13, wherein thedelivery shaft includes a longitudinal fixator lumen for deploying atemporary fixator coupled to a distal end of the delivery shaft.
 15. Alead delivery device comprising: a medical lead; an elongated deliveryshaft insertable to an anatomic target site of a patient, the deliveryshaft having a longitudinal delivery lumen with a closed channelcross-section; a hydraulic plug slidably received in the delivery lumen;and a flexible member coupling the medical lead to the hydraulic plugsuch that pressure exerted to the hydraulic plug through the lumenadvances the hydraulic plug and the medical lead toward the target site.16. The lead delivery device of claim 15, further comprising an externalring surrounding the delivery shaft and connected to the flexiblemember, the ring magnetically coupled to the hydraulic plug.
 17. Thelead delivery device of claim 15, further comprising a vent opening inthe delivery shaft.
 18. A lead delivery device comprising: a medicallead; an elongated delivery shaft insertable to an anatomic target siteof a patient, the delivery shaft having a first longitudinal deliverylumen and a second longitudinal delivery lumen separate from andsubstantially parallel to the first delivery lumen and communicatingwith the first delivery lumen through a U-shaped junction; a hydraulicplug slidably received in the first delivery lumen; and a flexiblemember connecting the medical lead to the hydraulic plug and passing bya pulley structure therebetween, such that applying pressure through thesecond delivery lumen in a direction toward the target site moves thehydraulic plug in the opposite direction and advances the medical leadtoward the target site.
 19. The lead delivery device of claim 18,further comprising a sealing member between the delivery shaft and theflexible member.
 20. A lead delivery device comprising: a medical lead;an elongated delivery shaft insertable to an anatomic target site of apatient, the delivery shaft having a longitudinal delivery lumen with aclosed channel cross-section; a hydraulic plug slidably received in thedelivery lumen; and a flexible member connecting the medical lead to thehydraulic plug and passing by a pulley structure therebetween, such thatapplying vacuum suction through the delivery lumen in a direction awayfrom the target site moves the hydraulic plug away from the target siteand advances the medical lead toward the target site.
 21. The leaddelivery device of claim 20, further comprising a vent opening in thedelivery shaft, the flexible member passing through the vent opening.22. A lead delivery device comprising: an elongated delivery shaftinsertable to an anatomic target site of a patient, the delivery shafthaving a longitudinal delivery lumen and a side opening communicatingwith the longitudinal lumen; a medical lead having an enlarged distalportion, the medical lead inserted into the delivery lumen such that theenlarged distal portion is distal to the side opening; and a flexiblesealing member at the proximal end of the delivery shaft, the sealingmember surrounding the medical lead, such that applying pressure throughthe side opening advances the medical lead toward the target site.